skypi
Posts: 111
Joined: Sat Aug 09, 2014 11:48 pm

enabling bluetooth on pi zero actually wrecks the whole wifi network

Thu Sep 05, 2019 3:49 pm

Strange one

I already suspected enabling bluetooth was wrecking the wifi and so on all 10 or so of my raspberrys I have bluetooth disabled in config.txt

wanted to use a blutooth gps and so on one node enabled blutooth, started to see all kinds of problems on other nodes on the wifi network

could not get any connection, so started a many hours long fault finding process and eventually disabled bluetooth on that device again (so bluetooth disabled on all devices again) and pings to all nodes back down to generally sub 10ms, and all comms good

so somehow bluetooth is screwing with the wifi. (or enables someone else to screw with the wifi)

is this a known problem on earlier pi zero W 's

wolf.z
Posts: 95
Joined: Thu Dec 24, 2015 8:34 pm

Re: enabling bluetooth on pi zero actually wrecks the whole wifi network

Thu Sep 05, 2019 9:10 pm

WIFI except those with an a following IEEE802.11 and bluetooth share the same radio frequency band. Using both causes some degradation in radio performance. Typically no wreckage happens. So the only chance, bluetooth migth screw up your WIFI physically was if many other WIFI networks compete and switching on the Bluetooth is the last percent of interference to cause a breakdown. I do not suspect this.
Think of bluetooth as a small-scale WIFI. It acts as a small-scale network. By using 10 or so Pis you suggest having many projects underway. So I suspect you having raised a true network connectivity via bluetooth somehow on some network device. Now, if you span two (wireless) networks connected, you might have created a data route loop.
Is there any Bluetooth master other than the Bluetooth enabled on the very one Pi you described?

skypi
Posts: 111
Joined: Sat Aug 09, 2014 11:48 pm

Re: enabling bluetooth on pi zero actually wrecks the whole wifi network

Fri Sep 06, 2019 12:36 am

One project, many test nodes.

It is as I described, opened up bluetooth for one device and wifi screwed (that is to say my desktop was having problems communicating with wifi nodes and nodes having problems communicating with each other), when I shut off bluetooth all back to good wifi comms.

plenty of other reports on net of having to use a bluetooth dongle to get wifi and bluetooth to co-exist on raspberry... (I guess you would only typically plug in the dongle when you wanted to use it and the trusted device connected stops any masquerade of being a trusted device)

if you live in a middle class and upwards area, maybe a better class of neighbour... more distance between wifi base stations for a start!

I suspect a tricksier problem!

That is to say, istm there should be no bluetooth (4 digit pin) to wifi (128 bit security) bridge , but perhaps is... (and if so... those responsible should be thrown off a bridge)

just using a gps dongle.

skypi
Posts: 111
Joined: Sat Aug 09, 2014 11:48 pm

Re: enabling bluetooth on pi zero actually wrecks the whole wifi network

Fri Sep 06, 2019 1:55 pm

Of course could be one of those coincedences, that I disabled bluetooth at the time the network just got better anyway, but that is certainly what seemed to fix it.

And in fact, just now I tested it again with the pi zero in access point mode and anecdotally, connecting to it to access a python flask web page was not really working when I had bluetooth enabled, disabled bluetooth and rebooted and access to the web page was OK.

fortunately I have found my old usb gps and so no need for bluetooth again.

But doing some background reading on hacking possibilities of bluetooth it seems a bit dodgy anyway if you have a device that is not always connected and someone has been bluetooth snooping and can see the handshake data of that paired device. Don't know the intricacies, not got time to waste on it, when as is often common with these types of things you spend ages working round a thing only to discover it is fixed soon after you get it worked round and so the entire amount of time is totally wasted!!!!

I would suggest that as default in the bluetooth.conf that power is not on, which is the default, but the raspbian supplied config files set power on in the config file as default.

obviously there is a conflict of interests between noobs who might want bluetooth to just work and those who have seen that it impacts on the network,

and this interference might be some known but swept under the rug bug feature of an early version of the wifi chip which could be actually fixed in current zero and pi3/4 ???

Also I am still running stretch, thought I would give the latest release time to bed in.

Return to “Troubleshooting”